Ozone is a powerful oxidizing agent. The reaction of ozone with organic compounds in aqueous media has achieved a variety of treatment goals. The advantage of ozonation over the other oxidants is that the degradable products of ozonation are generally non-toxic, its final products are CO2 and H2O, and also the residual O3 in the system changes in few minutes to O2 .Convential treatment of textile wastewater includes various combinations of biological (activated sludge), physical and chemical processes. The dyestuffs existed in these wastewater are highly structured organic molecules which are hardly break down biologically. Decolorization of two types of dyes, Direct Pink 3B and Reactive Violet SH- 2R, by ozonation in aqueous medium was studied in presence of some effective variables.These variables were: the rate of ozone generation, ozone dose, current, pH and the initial concentration of the wastewater. The total quantity of ozone generated is determined from the calibration curve of the ozoniser performance, while the unused ozone is determined from the titration of iodine liberated; the difference being the amount of ozone actually used in the reaction. It was found that 98% decolorization occur in few minutes. Data on time of ozonation, temperature and other chemical variables were discussed. This research proved its success as a method for treatment of wide concentration range from the dye wastewater (100-1000 ppm), so it overcomes the problems of textile wastewater treatment.